https://orcid.org/0009-0004-3889-2638
Abstract
Background
Over the past several years, there have been several changes affecting the available options for oral HIV preexposure prophylaxis, including approvals for tenofovir alafenamide with emtricitabine in 2019 and a generic formulation of tenofovir disoproxil fumarate with emtricitabine in 2020.
Methods
In order to better understand providers’ decision-making processes when deciding between these two drugs for pre-exposure prophylaxis, we conducted semi-structured in-depth interviews with resident, fellow and attending physicians in internal medicine and infectious diseases between May 2020 and March 2021. These interviews were analyzed to identify emergent codes, which were utilized in an inductive thematic analysis to identify major themes pertinent to pre-exposure prophylaxis decision-making.
Results
Of 21 participants, 18 expressed a general preference for prescribing tenofovir disoproxil fumarate with emtricitabine, 2 preferred tenofovir alafenamide with emtricitabine and 1 had no specific preference. Providers perceived similar efficacy of the two formulations, and their clinical decisions were influenced primarily by whether HIV pre-exposure prophylaxis users belonged to a population with an indication for each of the two drugs (e.g. gender-related restrictions for tenofovir alafenamide), the medications’ differing side effect profiles, cost and insurance considerations, prior personal and collective experience with each of these medications, and personal preferences. Respondents also noted that both providers and HIV pre-exposure prophylaxis users were influenced by external factors, including institutional prescribing guidance, advertising, and social influences, including from peers and colleagues.
Figures
Citation: Merchant E, Solleveld P, Gibas K, Krakower D (2024) Health care providers’ decision-making and early adoption of tenofovir alafenamide for HIV preexposure prophylaxis: An inductive qualitative study. PLoS ONE 19(12): e0311591. https://doi.org/10.1371/journal.pone.0311591
Editor: Carmen María González-Domenech, University of Malaga: Universidad de Malaga, SPAIN
Received: June 20, 2024; Accepted: September 20, 2024; Published: December 5, 2024
Copyright: © 2024 Merchant et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the paper and its Supporting Information files.
Funding: This was work was supported in part by the Harvard University Center for AIDS Research (P30 AI060354). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have read the journal’s policy and have the following competing interests: Fenway Health served as a recruitment site for this study. This does not alter our adherence to PLOS ONE policies on sharing data and materials.
Introduction
There are an estimated 30,635 new cases of HIV annually in the United States, highlighting the need to implement effective HIV prevention strategies [1]. Studies have demonstrated the effectiveness of tenofovir disoproxil fumarate with emtricitabine (TDF/FTC) taken daily as HIV preexposure prophylaxis (PrEP), and there have been very few documented HIV infections in people adherent to PrEP at the time of infection [2]. TDF/FTC taken daily for PrEP was approved by the Food and Drug Administration (FDA) in 2012 for adults, with the indication expanded to include adolescents in 2018 [3].TDF/FTC was initially marketed exclusively under the brand name Truvada by Gilead Pharmaceuticals. Starting in October 2020, a generic alternative became available, and in March 2021 multiple generic options became accessible, greatly reducing its price [4].
The first alternative to daily TDF/FTC to be approved by the FDA for PrEP was tenofovir alafenamide with emtricitabine (TAF/FTC, manufactured by Gilead Pharmaceuticals under the brand name Descovy) in October 2019, approved for adults and adolescents at risk for sexually-acquired HIV, excluding those at risk from receptive vaginal sex [3]. TAF/FTC was demonstrated to be non-inferior to TDF/FTC for the prevention of new HIV infections among men who have sex with men and transgender women in the DISCOVER trial [5]. TAF/FTC was formulated to reduce the potential for adverse renal outcomes and decreased bone mineral density (BMD) associated with use of TDF/FTC when used as part of combination treatment for HIV infection. In studies of PrEP, TDF/FTC has been associated with mild decreases in renal function that typically normalize after discontinuing PrEP, and with decreases in bone mineral density (BMD) not associated with increased fracture rates [6, 7]. In the DISCOVER trial, significant differences were noted in bone and renal biomarkers among those using TDF/FTC versus TAF/FTC; however, there were no differences between these drugs in rates of discontinuing PrEP for bone or renal harms. Overall clinical adverse events were similar between the TAF/FTC and TDF/FTC arms, as TAF/FTC was associated with greater weight gain and altered lipid parameters [5].
Soon after the approval of TAF/FTC for HIV treatment, this formulation largely supplanted TDF/FTC in combination regimens because of its lesser impact on renal and bone biomarkers among people living with HIV, a population at increased risk for renal and bone disease. For PrEP, given the similar safety profiles of these formulations and their use in populations without specific risks for renal and bone disease, cost-effectiveness studies have found that using generic TDF/FTC instead of branded TAF/FTC would offer substantial cost savings [8]. The objective of our study was to examine health care providers’ perceptions, attitudes and prescribing behaviors for TDF/FTC versus TAF/FTC during the first two years following FDA approval of this second PrEP option, which could inform strategies to optimize use and cost-effectiveness of oral PrEP in an era of limited resources for HIV prevention in the US.
Methods
Study design and setting
We explored providers’ approaches to prescribing TAF/FTC or TDF/FTC for PrEP using inductive qualitative methods with semi-structured in-depth individual interviews [9]. This method was chosen to provide insight into individual providers’ understanding, attitudes and practices regarding their choice in PrEP regimens. This study was conducted in Boston at Beth Israel Deaconess Medical Center (BIDMC), an academic medical center, and Fenway Health, a community health center specializing in healthcare for LGBTQIA+ populations. The study was deemed exempt by the Institutional Review Boards of Fenway Health (3/2020) and BIDMC (4/2020).
Researcher characteristics
The research team was composed of an infectious diseases attending physician (D.K), and Infectious Diseases fellow (E.M), an internal medicine resident who subsequently became an infectious diseases fellow (K.G.) and a research assistant (P.S., research assistant to D.K). One of the authors (DK) has published other work on PrEP decision-making, potentially leading to social desirability bias in participants’ responses. To mitigate this potential bias, interviews were not conducted by this investigator, transcripts were anonymized prior to his review, and our team members engaged in reflexivity (i.e. self-conscious appraisal and critique to minimize subjectivity in data analysis and interpretation) to reduce bias from preconceived notions about PrEP options [10]. Moreover, interview questions were asked in a neutral manner, with the same questions asked about both TAF/FTC and TDF/FTC, and participants were asked to provide candid answers in an effort to minimize bias. To further reduce bias the authors engaged in deliberate and frequent reflexivity throughout the study, from the development of the interview guide through the drafting of this manuscript. This included revising documents with an explicit eye towards unbiased and neutral collection, analysis, interpretation, and dissemination of data.
Participant recruitment and interviews
Between May 2020 and March 2021, we extended email invitations to prescribing clinicians at BIDMC and Fenway Health using purposeful sampling to enroll 1) providers from both health care organizations, 2) faculty and trainees, and 3) primary care providers (PCPs) including internal medicine (IM) residents, and infectious diseases (ID) specialists, to capture multiple perspectives [11]. Most providers sampled had professional relationships with at least one member of the interview team, working at the same medical facility. There were no incentives provided for participation. Eighteen of the 39 providers emailed either did not respond to the email or stated they did not have time to participate. 21 providers responded to the email and agree to participate. No participants dropped out of the study. Participants were informed that the research was investigating decision-making around PrEP prescribing. Interview domains included awareness, perceptions and influences on prescribing TAF/FTC versus TDF/FTC, experiences using TAF/FTC PrEP, current prescribing practices for PrEP, and user experiences with oral PrEP formulations.
Interviews were conducted one-on-one by K.G., (male IM resident) or E.M. (female ID fellow) between May 2020 and April 2021 using secure video chat or in person at the hospital, after obtaining informed consent. Interviews were semi-structure based on a pre-formulated interview guide with each interviewee asked the same set of pre-specified questions, with ad-lib follow-up questions as determined by the interviewer. All interviewees answered all questions posed. Each participant was interviewed only once, with interviews lasting approximately 30 minutes. Interviews were audio-recorded and transcribed verbatim, with hand-written notes taken during the interviews. A brief quantitative survey was used to collect data on participants’ demographics and experiences with PrEP prescribing prior to the interviews. Interviews were conducted until saturation was reached, with no new codes or themes from the last 4 interviews conducted, confirmed with a saturation grid and review by two team members (E.M., D.K.) [12].
This study was deemed exempt by both the Institutional Review Boards of Fenway Health and BIDMC. The study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki. Verbal informed consent, including consent for publication, was obtained prior to the interview from all individual participants included in this study.
Data analysis
Interview transcripts were analyzed using DeDoose software. Interview transcripts are available in S1 File. The researchers first assembled a preliminary list of codes based on extraction of concepts relating to our research questions during a detailed review of the raw data (i.e., interview transcripts). Next, the researchers together engaged in data reduction by simplifying, combining or renaming codes from the full list to be as parsimonious as possible without compromising comprehensiveness. Codes were categorized according to their relationship to the domains of our semi-structured interview guide as well as additional, unanticipated categories pertinent to our research aims. Finally, emergent themes relating to our research questions were described by the researchers based on these categories, and these themes were revised in an iterative manner through ongoing discussions amongst team members, including with application of reflexivity to mitigate bias. All transcripts were then coded by E.M., with a subset of 20% separately coded by P.S. to assess inter-rater reliability. E.M., P.S. and D.K. reviewed each incidence of discrepant coding and came to an agreement on the appropriate code. An inductive thematic analysis was utilized to identify a thematic framework from the codes [9].
Results
Survey of provider characteristics
39 participants (7 ID attendings, 17 attending PCPs,10 ID fellows, and 7 IM residents) were invited via email and 21 enrolled (2 ID attendings, 5 attending PCPs, 8 ID fellows, 6 IM residents). A majority of participants were under 32 years-old (13, 61.9%), cis-gender men (12, 57.1%), and white (11, 52.4%). (Table 1) Most participants had been practicing for 0–5 years (16, 76.2%), and nearly provided care for people on PrEP (17, 81%) or living with HIV and on antiretroviral treatment (19, 90.4%).
Two providers indicated that they preferentially used TAF/FTC (ID fellows at the academic medical center), 18 providers preferred TDF/FTC and 1 provider did not express a preference (IM resident at the academic medical center) (Table 1).
Thematic analyses
We identified 7 major themes relating to providers’ selection of TAF/FTC versus TDF/FTC; we describe these and provide illustrative quotes in Table 2. Providers perceived similar efficacies between the two drugs. Many providers noted that they preferred TDF/FTC due to FDA approval for a broader range of populations. Discussion of side effect profiles was a common theme, with providers noting concerns over potential renal and bone harms with TDF/FTC and concerns about metabolic toxicities with TAF/FTC. Providers cited greater experience with the safety and efficacy of TDF/FTC as a factor favoring this formulation. On the other hand, providers incorporated PrEP user knowledge and preferences and noted greater PrEP user awareness of the side effects associated with TDF/FTC versus TAF/FTC. Financial and insurance issues were felt to favor TDF/FTC, largely related to the recent release of its generic formulation. Providers identified several external factors that influenced the decision between TDF/FTC and TAF/FTC including institutional prescribing guidance, advertising, and social influences, including from peers.
Theme 1: Providers believed that TDF/FTC and TAF/FTC have similar efficacy.
Many providers perceived that the two drugs were of similar efficacy and none expressed concerns that either drug was less efficacious. (Table 2) “In my mind TAF and TDF are equivalent apart from their side effect profile[s].” (ID fellow) Given similar efficacy, providers used other factors to drive decisions, such as side effects and cost.
Theme 2: Providers favored TDF/FTC for PrEP because it is FDA-approved for all populations.
Providers noted that TAF/FTC has currently only been studied in and approved for people who do not engage in receptive vaginal sex (e.g. men who have sex with men [MSM] and transgender women [TGW]), which contributed to their preference for TDF/FTC. “The DISCOVER trial was limited… only using MSM and trans women, so we don’t know essentially yet if it’s generalizable, so I wouldn’t use it also for those practicing receptive vaginal sex.” (Attending primary care provider) Some providers felt that based on its more limited evidence-base, they would not use TAF/FTC in people with HIV risk factors outside of its approved indications, such as vaginal sex or injection drug use. However, other providers felt that the limited evidence and lack of FDA approval for use of TAF/FTC for people who engage in vaginal sex or people who inject drugs (PWID) might be outweighed by other considerations, such as renal comorbidities.
Theme 3: Differing safety profiles was the primary consideration when choosing between TDF/FTC and TAF/FTC.
Every provider mentioned they would consider side effect profiles and user comorbidities when choosing between TDF/FTC and TAF/FTC. A dominant theme was how the potential nephrotoxic effects of TDF/FTC affected decision-making, particularly for people with or at risk for renal dysfunction, however concerns about decreased BMD with TDF/FTC were also commonly noted. “I think if [a patient] already has a GFR that is impaired, if they’re in that 30–60 range for their GFR,… I think that TAF is reasonable.” (Internal medicine resident) Providers considered the potential toxicities associated with TDF/FTC to be reversible or clinically insignificant, which mitigated concerns. While nephrotoxicity and bone harms were the primary concerns with TDF/FTC, weight gain and metabolic effects were among the most commonly cited concerns about TAF/FTC. Some expressed beliefs that the weight gain was more clinically significant and less reversible than the side effects associated with TDF/FTC. “I think if someone was overweight or obese or had family history,… it might make me move towards the Disoproxil formulation… especially considering that the renal impairment and the bone changes with the disoproxil form are reversible… But, I mean weight gain is also weight gain and It’s hard for people to lose weight.” (Internal Medicine Resident)
Providers cited age and anticipated duration of PrEP use as factors in drug selection, although there was not a consensus as to the optimal drug for younger or older PrEP users. The perceived younger age and good health of PrEP users assuaged some providers’ concerns about TDF/FTC toxicities. However, other providers felt that younger people might have a longer duration of treatment and therefore favored the diminished renal and bone toxicities of TAF/FTC, analogous to their approach for people living with HIV. Some providers felt that older age raised concerns about the potential renal and bone toxicities of TDF/FTC, while others felt older age was a reason to avoid potential metabolic toxicities with TAF/FTC. Some felt age did not influence their decision between TAF/FTC and TDF/FTC, because all toxicities could increase with advanced age.
A minor consideration was perceived tolerability, either due to gastrointestinal (GI) side effects associated with TDF/FTC or the smaller pill size of TAF/FTC.
Theme 4: Providers favored TDF/FTC because of greater experience and familiarity with this medication.
A recurrent pattern was that positive first-hand experiences and longer collective duration of prescribing TDF/FTC for PrEP increased comfort with this formulation. Some providers felt that habit contributed to their continued use of TDF/FTC. “I’m still pretty much prescribing Truvada,… because that’s what I’ve always done, and it’s what was out there first. And I feel like the number of patients that I’ve had on it, I think I’ve only had one patient so far that had any um, renal impairment, that has had any toxicity that I can measure from it. Despite having patients that have been on it for, you know, years, for prevention. And so I still feel pretty safe with it.” (Infectious diseases attending)
Theme 5: Providers integrated PrEP users’ preferences into prescribing decisions, in particular knowledge of potential toxicities with TDF/FTC and interest in using TAF/FTC.
Providers described varied levels of PrEP user knowledge about the differences between TDF/FTC and TAF/FTC, from no awareness to being well-informed. This knowledge was perceived as coming from social networks, advertisements, personal research and experience. PrEP user inquiries or requests were more common for TAF/FTC, and people were particularly aware of the potential toxicities of TDF/FTC. This knowledge was perceived to come largely from friends, media, and awareness of lawsuits claiming damages from use of TDF/FTC. Some PrEP users seemed to assume that TAF/FTC was “safer” than TDF/FTC because it is “new”. Providers felt that there was less recognition among PrEP users of metabolic toxicities with TAF/FTC.
Providers varied in their use of provider-dominant, patient-dominant or shared decision-making for PrEP selection. Some providers initiated the discussion of the two options routinely, while others only addressed options when brought up by patients. “I usually have a conversation with the patient and ask them if they’ve heard of both… Which sometimes they have, and then, kind of explain the differences.” (Infectious diseases fellow) When providers’ and PrEP users’ preferences differed, the general approach was to defer to PrEP users.
Theme 6: Financial and insurance considerations favored TDF/FTC, especially with the approval of generic TDF/FTC.
Cost and insurance coverage played a role in providers’ decision-making, favoring TDF/FTC, which was perceived to be more cost-effective, in part related to the availability of generics. “The big concern would be that we would prescribe it (TAF/FTC) and the patient couldn’t afford it and maybe wouldn’t come back to clinic and kind of lose that ability to capture and establish care with them.” (Infectious diseases fellow) Some providers had PrEP users who had experienced these barriers with TAF/FTC, while others had not, citing financial support systems.
Theme 7: Providers believed that their PrEP recommendations were influenced by professional norms, institutional guidance, educational resources, and pharmaceutical advertising to PrEP users.
When asked about sources of influence for prescribing decisions, providers cited guidance from within their own institutions, clinical practices of colleagues (or preceptors for trainees), or didactic education. Many used online resources, including professional society guidelines, resources such as UpToDate.com, or literature reviews. Additional influences on providers included social media and pharmaceutical companies. Providers described direct-to-consumer advertising as an influence on PrEP users, acknowledging personal consumption of the same advertising seen by PrEP users; however, they did not identify their own exposure to advertising as a significant influence on their decisions. “It’s hard to avoid seeing it on commercials, but I don’t use commercials as a management tool.” (Attending primary care physician) This is consistent with prior studies showing that physicians are susceptible to influence from pharmaceutical advertising, although they may not recognize this influence [13]. A perception existed that a shift in advertising toward Descovy (TAF/FTC) from its manufacturer may have been spurred by the waning patent protection for TDF/FTC prior to the release of generic formulations.
Discussion
The availability of new PrEP formulations has the potential to improve its use, safety and impact, if new formulations offer advantages over existing options. However, it can also result in increased use of less cost-effective medications without population benefits. We interviewed primary care and infectious diseases providers about their experiences and approaches to deciding between TDF/FTC or TAF/FTC for PrEP, to learn about whether and how the availability of this new option might impact prescribing behaviors.
Our main themes suggest that providers were confident in the efficacy of either regimen for MSM. For some providers, a lack of proven efficacy for TAF/FTC in other populations, such as people engaging in vaginal sex or PWID, was an absolute contraindication, however others suggested they would consider off-label use of TAF/FTC in the setting of certain risk factors. A universal decision-making approach was to consider PrEP users’ comorbidities and the side effect profiles of PrEP formulations when deciding between TAF/FTC and TDF/FTC, with avoidance of TDF/FTC in people with a diagnosis of or risk factors for renal dysfunction or low bone mineral density. Some providers also avoided TAF/FTC in people with obesity or metabolic syndrome given potential for weight gain and dyslipidemia. Age was a common consideration in PrEP selection, however, given longer expected duration of use among younger people and increased comorbidities among older people there was not consensus about the optimal formulation to use at either end of the age spectrum.
PrEP user interest in TAF/FTC, generated by media, advertisements and social networks, influenced providers towards its use. This influence seemed to be balanced by providers’ concerns that PrEP users would ultimately wish to avoid the metabolic toxicities of TAF/FTC, particularly weight gain, even though people were less familiar with these effects than with potential harms from TDF/FTC. When met with uncertainty about the optimal choice for individual PrEP users, or when there was discordance between provider and PrEP user preferences, some providers asserted their recommendation, while others engaged in shared decision-making and many deferred to user preferences. Our findings suggest that educational messaging directed at PrEP users impacts prescribing decisions. Because direct-to-consumer advertisements by drug manufacturers may be biased towards drugs that increase their revenue, it will be in PrEP users’ best interests to disseminate unbiased information about PrEP options to them, such as through public health campaigns, as well as to providers through clinical training.
In an observational study in which 277 of 1009 people surveyed in 2019–2020 had switched from TDF/FTC to TAF/FTC, 56% indicated that the decision to switch was provider-led (without further details), 32% perceived TAF/FTC to be safer, 8% preferred its smaller pill size, and 6% had side effects or pre-existing medical conditions that influenced the switch. In a study of an online screening questionnaire for a trial of a PrEP adherence intervention in early 2020, most people were prescribed TDF/FTC, and self-reported PrEP adherence was greater with TAF/FTC than TDF/FTC, which was speculated to be related to treatment fatigue with TDF/FTC or beliefs that TAF/FTC had superior efficacy or improved side effect profile. Our study is consistent with these studies in that perceptions of differing safety profiles between TAF/FTC and TDF/FTC, currently seen through the lens of the providers, may promote continued use of TDF/FTC for most PrEP users and switches to TAF/FTC driven by perceptions of improved safety or smaller size.
Our finding for a provider preference for TDF/FTC in 2020 is consistent with studies published in 2021 showing that TDF/FTC still being prescribed as PrEP in a majority of cases [14, 15]. Subsequent data, though, has shown the growth of TAF/FTC prescribing for PrEP, with a retrospective observational study showing that TAF/FTC was prescribed in 86% of new PrEP starts between October 2019 and May 2021 [16]. An abstract published in 2023 analyzing the IQVIA Real-World data—Longitudinal Prescription Database found that there were more prescriptions for TAF/FTC than brand-name TDF/FTC from late 2020 until September of 2021, at which time generic TDF/FTC became the most commonly prescribed drug (currently representing 50.3% of prescriptions for PrEP, with TAF/FTC representing 45% of prescriptions, brand-name TDF/FTC 4.5% and injectable cabotegravir 0.5%) [17]. These findings are in concordance with our identified theme that a generic option for TDF/FTC moves providers towards this choice. However, it is striking that nearly half of all recent PrEP prescriptions were TAF/FTC despite the availability of a generic option of similar safety and efficacy, suggesting a need for further studies to understand how providers and PrEP users approach prescribing decisions for PrEP, to improve its cost-effectiveness.
Our study design has limitations. We enrolled providers from only two affiliated institutions in Boston, so our findings may not be generalizable outside of these two institutions, especially given the contributions of institutional culture on PrEP decision-making described by participants. The two institutions included represent a prototypical academic medical center and a community health center that is the largest PrEP provider in New England.
Additionally, interviews for this study were conducted during the time period in which generic TDF/FTC first became available (with a minority of interviews being conducted prior to availability of the generic), and views surrounding generic options may have changed over time.
Another limitation is that our data did not reveal themes relating to the influence of sociodemographics on PrEP prescribing decisions, which may have been due to a lack of attention to this topic in our interview guide. However, given prior work demonstrating that providers may have implicit biases that influence their prescribing of PrEP, such as being less likely to offer PrEP to Black individuals, future studies focused on how providers select among PrEP options should explore the topic of how sociodemographic factors affect prescribing decisions in more detail [18].
This study was also conducted prior to the 2020 approval of long-acting injectable cabotegravir (CAB-LA) given every 8 weeks for PrEP [19]. We additionally did not query providers on non-FDA-approved PrEP alternatives which have been shown to be effective in certain populations, including on-demand TDF/FTC PrEP (currently recommended by the World Health Organization [WHO]), and the dapivirine vaginal ring (currently recommended by the WHO but not available in the US) [20, 21].
This study highlights the need for further study into the providers’ decision-making processes around PrEP at other institutions and in other regions. Additionally, an important next step will be to further investigate the PrEP user perspective, which is only evaluated indirectly in this study.
In conclusion, we found that in the first two years after the availability of TAF/FTC for PrEP, providers at our institutions still generally preferred to prescribe TDF/FTC despite considering potential renal and bone adverse effects. Preferences for TDF/FTC were driven by perceptions that the potential harms from TDF/FTC were reversible and of minimal clinical significance, as well as familiarity with this formulation, approval for use in all populations, and fewer concerns about cost or insurance coverage. TAF/FTC was preferred primarily in people with risk factors or comorbidities that would put them at higher risk for renal or bone adverse effects, especially because providers also had concerns about metabolic toxicities from its use. However, providers experienced interest in TAF/FTC from PrEP users, which is perceived as being driven by social influences and advertising, which could also drive increased use of this formulation for clinicians who support shared decision-making with PrEP users. Our findings suggest that unbiased educational campaigns for providers and PrEP users will be important to support evidence-based prescribing practices and cost-effective decisions about oral PrEP options given the dramatic cost differences between generic TDF/FTC and branded TAF/FTC.
Acknowledgments
We would like to acknowledge the participants in our study for freely giving their time and thoughts.
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